Embodiments of the invention generally relate to the delivery of audio information over a network. More specifically, embodiments of the invention pertain to monitoring and evaluating the delivery of audio information over a network.
Traditionally, digital voice communication has relied primarily on circuit-switched networks. However, packet-switched networks (e.g., the Internet) are being increasingly used for voice communications. The adoption of packet-switched networks for voice communication has engendered a requirement for testing the capability of the packet-switched network to handle the unique requirements of voice transmission. Generally, this testing is referred to as Voice Quality Testing (VQT).
In general, there are a number of factors involved in determining voice quality. Some of these factors can be objectively measured, while others of these factors are more subjective in nature and hence more difficult to quantify. An example of the former is packet delay, and an example of the latter is clarity.
Internet-standard protocols such Real-Time Transport Protocol (RTP) and Real-Time Control Protocol (RTCP) provide the capability for measurement of the more objective factors. Examples of industry-standard techniques for measurement of the more subjective factors include Perceptual Speech Quality Measurement (PSQM), Perceptual Analysis/Measurement System (PAMS), and Perceptual Evaluation of Speech Quality (PESQ).
A problem with conventional voice quality testing is that the different types of information available for evaluating audio (e.g., voice) quality in a network are disparate and incoherent, making it difficult to assess network capability and to identify the causes of any degradation in performance.